Urinary catheters bypass the normal bladder process of storing urine, and only releasing the urine by using the bladder detrusor muscle. Catheters can be a necessary tool to open the bladder to allow urination when patients have trouble urinating. A catheter can be a lifesaving tool since an uncontrolled buildup of urine can cause serious medical problems including death. However, there are known problems with catheters.
Struvite crystal encrustation is the effect of stagnated urine in the neck of the bladder when using a catheter. In the face of an indwelling catheter, urine can pool at the neck of the bladder, and the pooled urine can shift from a normal pH factor to an abnormal pH level of 10 or more while it stagnates. Urine shifts to an ammonia state where struvite crystals can precipitate and enlarge on the indwelling catheter. This situation can occur as the bladder loses its natural ability to cyclically flush itself in the face of an indwelling catheter. Bladder wall thickening has also be observed in long-term catheterizations and may be a result of the increasing pH levels.
Urinary tract infections can occur as the urine stagnates and shifts from its normal, acidic antibiotic property through the pH spectrum. Pooled urine that can occur in the neck of the bladder beneath the indwelling catheter can be a natural breeding ground for microbes which can migrate in the body.
Bladder spasms can also occur with an indwelling catheter which causes the bladder to cease its normal cycle of filling and flushing. A dynamic functioning system is converted to a static state with a catheter, and painful bladder spasms can occur. Bladder atone can also occur where short term or more permanent loss of natural bladder functions occurs by using a catheter.
It is also generally well known in medical circles that a human bodies primary defense mechanism against urinary track infections and the other problems listed above is the process known as xe2x80x9cwash-outxe2x80x9d, where it is advantageous to allow a bladder to normally fill up and be released at one time rather than in an uncontrolled drip fashion that would occur with using a catheter.
Various catheter type instruments and procedures have been used for draining bladders of patients in hospitals. These instruments and procedures have evolved from constant (non-cycling) drip drainage through painfully inserted catheters by siphoning, suction and various types of awkward manually externally controlled cycling apparatus and procedures. Fundamental to an effective, safe, and appropriate device and method is allowing the bladder to fill reasonably and then draining it without a suction pump and without allowing build-up or entry of infectious contaminants in the drainage system.
Included in previous methods and devices have been U.S Pat. Nos. 2,602,448 and 2,860,636 which utilized a siphon in combination with a reservoir to provide cyclic draining of the bladder. Pressure release in these devices is controlled by raising the height of the device on a bedside tree. It is subject to distortion by shifting and turning of the patient and is unreliable (and can compromise safety) besides restricting the patient.
U.S. Pat. No. 3,598,124, describes a siphon leg controlled by merely attaching a catheter to a bedside tree at predetermined adjusted height, which varies the pressure at which the bladder will drain and provides a flutter valve near the patient to break the siphon action of the system once the bladder has drained.
U.S. Pat. No. 4,230,102, describes a device for the draining of a bladder in which a T-joint has been placed on a catheter and has a pressure membrane attached thereto in a large casing for actuating a pressure switch which in turn actuates an electric motor driving a gear train and cam. A cam follower is spring loaded to clamp the catheter for two minute cycles upon actuation by the pressure switch to drain the bladder. However, this type of device, can be expensive and bulky and positions an electrical apparatus adjacent to the catheter.
U.S. Pat. No. 4,424,058, describes a spring-return valve in conjunction with a siphon-release orifice to prevent excessive suction and to prevent urine from remaining in the system after drainage. A problem with this system was that the restoring force of the spring increased with distance of travel from a closed position. This valve was very unsatisfactory because it closed again as soon as the urine fluid pressure dropped off, thus causing fluid to remain trapped in the bladder to stagnate with further elapsed time. Only a full bladder would open it, sometimes at an uncomfortably high (and potentially unsafe) pressure, and only a relatively full bladder would keep it open to allow complete drainage unless overridden by the patient bearing down heavily on the lower abdomen. Also, positioning of tubes leading from it was parallel to the leg on which it was attached and provided a situation for retention of fluid in the system.
None of the proposed patented devices and techniques described above solves all the problems with catheters that are listed above.
Unlike the problem methods and devices of the prior art, the subject invention provides both consistent magnetic opening and closing of a valve seal with decreased rather than increased closing pressure when opened. As the bladder is emptied, decreasing head pressure against the valve can keep the valve open to establish complete and sterile drainage. In addition, the successfully-tested clinical embodiment of this invention provides simple and convenient manual override, when desired, to decrease or eliminate totally the magnetic closing pressure of the valve.
A primary objective of the invention is to provide a low pressure magnetic valve for bladder management cyclic flow control having consistent opening and closing of the valve seal with decreasing head pressure against the valve as opposed to increasing pressure. As long as any fluid is coming through the line, the valve will remain open until a complete emptying of the bladder is achieved.
A secondary objective of the invention is to provide a low pressure magnetic valve for bladder management cyclic flow control that establishes complete and sterile drainage as the bladder is being emptied.
A third objective of the invention is to provide a low pressure magnetic valve for bladder management cyclic flow control that can be automatically run with a simple and convenient manual override that can be selectively engaged.
A fourth objective of the invention is to provide a low pressure magnetic valve for bladder management cyclic flow control that helps restore normal body functions of bladder filling and emptying in a cyclic manner, with normal, healthy pressure sensations in spite of the presence of the catheter which typically inhibits xe2x80x9cnaturalxe2x80x9d bladder drainage.
The fifth objective of the invention is to provide a low pressure magnetic valve for bladder management cyclic flow control for use with a catheter which can reduce and eliminate known problems that occur with using a catheter such as urinary tract infections, struvite crystal encrustation, bladder spasms and bladder atone.
The sixth objective of the invention is to allow a user wearing a catheter to use their bladder detrusor muscle to selectively turn on a valve in the catheter and complete an entire urination emptying cycle of their bladder.
The invention provides for both consistent magnetic opening and closing of a valve seal with decreased rather than increased closing pressure when being opened. As the bladder is being emptied, the decreasing of head pressure against the valve can keep the valve open to establish a complete and sterile drainage.
In the invention, valve-closing pressure can decrease as a result of three important factors: (1) magnetic pull of a valve decreases as its open distance from magnetic attraction in the direction of the valve seat increases, (2) the gravity-enhanced fluid flow column in the drain down tube provides a slight negative pressure on the back side of the movable magnet (thus tending to hold the valve open until the drain tube empties completely), and (3) fluid passing through the system provides a partial mass flow insulation which tends to hold the moving magnet away from the fixed magnet, also decreasing the net magnetic attraction between the magnetic members. A small amount of air is allowed to leak through a micro-pore filter (which keeps out harmful micro-organisms from the closed system) in order to vent the down line for clean, dry emptying.
The very low-pressure valve system of the invention for use in controlling the flow of most fluids utilizes magnetic forces to hold a smooth surface against an ultra low-durometer (soft) composite seal or valve seat material until such time as the fluid head pressure causes the magnets to separate and the valve to open, at a preset value, to allow maximum fluid flow rate and complete drainage of the system
The use method described here is medical in nature, applying to bladder drainage of catheterized patients into a urine collection bag, as needed, in a normal, cyclic fashion. In other words, head pressure of urine building up in volume against the detrusor muscle of a bladder and in a catheter running from the bladder to the valve where it is positioned on a patient""s leg or rests on the bed sheet, causes the valve to open away from the valve-port seat. When the valve is opened, distance increases between the valve magnetic member and a member to which it is magnetically attracted in the direction of the valve-port wall, thereby allowing the valve to remain open with less pressure than that initially required to open it. Fluid passing between the open valve and the member to which it is attracted magnetically decreases further still the closing pressure to offset the head-pressure opening of the valve.
Downstream from the valve, there is a siphon-release air-inlet orifice that relieves siphon (negative pressure) to avoid siphon suction that would either cause collapse of the bladder walls or cause the valve to remain open after the bladder is emptied. An air inlet, allowing only air flow through a micro-pore filter material to the siphon-release orifice, is positioned upstream and radially outward from an outlet to the valve in order to prevent passage of fluid from the valve where siphon pressure does not provide sufficient inward suction of air. The siphon-release orifice is provided with an antiseptic strainer (anti-bacterial/anti-viral filter) and can serve as a low-pressure one-way inlet valve.
The entire valve system (in the embodiment of a small, streamlined, compact, integrated and durable device) also serves as an anti-reflux valve between the patient and the urine collection bag, thus preventing drained (and possibly old and unsterile, septic, contaminated) urine from ever re-entering the catheter, urethra, and bladder of the patient, and potentially causing infection or other problems.
Additional embodiments of this invention provide for a manual override of the valve by selective distancing an externally positioned magnetic member from the valve member that is attracted to it. The override gives flexibility of pressure adjustment and provides the opportunity of assuring full drainage when desired by either physician or the patient. This could manifest itself, in the event of excessive discharge of viscous matter or other mode of lumen blockage, as a xe2x80x9csafetyxe2x80x9d valve to relieve fluid pressure buildup.
An additional swivelable attachment of the bladder cycler to a strap on a patient""s leg can allow the cycler to be positioned comfortably at a slant with the outlet and tubes leading from it downward from the valve to further assure that fluid will not remain in the system between drainage cycles whether used in either a prone or vertical position of the leg. The patient also can more readily move about and not be confined or attached to the bed as long as the collection bag is kept attached for use as needed.
The invention can be used as a hospital instrument whenever an indwelling catheter is required, or in clinics, or in physician""s offices, or in homes for draining urine from bladders of patients automatically and safely after normal filling, thoroughly and antiseptically. This use is in strong contrast to the typical, non-cyclical, continuous drip associated with urethral catheter drainage into a collection bag. The use of the UroCycler with catheterized patients helps restore the more normal body function of bladder filling and emptying in a cyclic manner, with normal, healthy pressure sensations in spite of the presence of the catheter which here-to-fore prevented xe2x80x9cnaturalxe2x80x9d bladder drainage.
Further objects and advantages of this invention will be apparent from the following detailed description of the presently preferred embodiments which are illustrated schematically in the accompanying drawings.